Door locks which comprise a device for detecting a closed state of a household appliance door, a device for locking and optionally for unlocking the household appliance door and a device for detecting a locked state of the household appliance door are known in the household appliance sector.
The device for detecting the closed state establishes whether the household appliance door (also door in brief in the following) is closed. In this respect a closed state of the door is to be understood as meaning that the door closes the associated opening of the household appliance, if necessary with a sealing action, i.e. is not just ajar. It is assumed in the following that the door must be in the closed state if it is to be locked. It is of course also possible for the door not to be locked when it is in the closed state.
If the door is in the closed state, for example when starting up the household appliance, the device for locking can be actuated in order to lock the closed door, i.e. to bring it into a state in which the door cannot be opened.
If the door is locked, this is recognised by the device for detecting the locked state.
The device for detecting the closed state of the door provides a signal which indicates that the door is closed. This signal indicates to a control of the door lock that the door is closed and can now be locked. The device for locking is subsequently activated by the control in order to lock the door. The device for detecting the locked state of the door provides a signal which indicates that the door is locked. This signal indicates to the control that the door can no longer be opened and it is accordingly possible to operate the household appliance.
A known door lock for washing machines is illustrated in detail with reference to FIGS. 1 to 3:
The door lock, which is designated as a whole by 100, has a housing shell 102 in which components which are described in the following are disposed. A housing lid, which is not represented, serves to close the equipped housing shell 102 and, together with the housing shell 102, forms the housing of the door lock 100.
A main slide 104, which can be displaced horizontally in the figures, is disposed in the housing shell 102. A main slide spring 106 acts on the main slide 104. The main slide 104 has a stop 108, the function of which is described in greater detail below.
A device of the door lock 100 for detecting the closed state of a household appliance door comprises a door contact switch 110. The door contact switch 110 has a first door contact 112 and a second door contact 114. If, as shown in FIG. 1, the first and second door contacts 112 and 114 are separated from one another, this indicates that the door is open. If, as shown in FIGS. 2 and 3, the first and second door contacts 112 and 114 contact one another, this indicates that the door is closed.
The first door contact 110 is disposed adjacent to a free end 116 of a first door contact conductor 118 formed as a leaf spring. The first door contact conductor 118 is biased to the right in the figures, i.e. the free end 116 exerts a force which is directed to the right. The end 120 of the first door contact conductor 118 which lies opposite the free end 116 is fastened to an inner end (not designated) of a first connection contact 122. This can take place by gluing, soldering or riveting, for example. The first connection contact 122 is formed as a rigid, stiff conductor. The end 120 of the first connection contact 122 which lies opposite the connecting point with the first door contact conductor 118 serves the purpose of connection to a plug connection, which is not represented, of the household appliance.
The second door contact 114 is disposed at one end 124 of a second door contact conductor 126. The second door contact conductor 126 is formed as a rigid, stiff conductor. Movements of the first and second door contacts 112 and 114 relative to one another are therefore possible on account of the flexible configuration of the first door contact conductor 118. The end 128 of the second door contact conductor 126 which lies opposite the end 124 forms a second connection contact 128 and serves the purpose of connection to the above-mentioned plug connection.
A device of the door lock 100 for detecting a locked state of a household appliance door comprises a locking contact switch 130. The locking contact switch 130 has a first locking contact 132 and a second locking contact 134. The first locking contact 132 is disposed adjacent to a free end 136 of a first locking contact conductor 138 formed as a leaf spring. The first locking contact conductor 138 is biased to the left in the figures, i.e. therefore exerts a force to the left. The end 140 of the first locking contact conductor 138 which lies opposite the free end 136 is fastened to a third connection contact 150 by soldering, gluing or riveting, for example. The end of the third connection contact 150 which lies opposite the connecting point with the first locking contact conductor 138 serves the purpose of connection to the above-mentioned plug connection.
The second locking contact 134 is disposed at one end 144 of a second locking contact conductor 146, which is formed as a stiff, rigid conductor. The opposite end of the second locking contact conductor 146 forms a fourth connection contact 142 and serves the purpose of connection to the above-mentioned plug connection.
A device of the door lock 100 for locking and unlocking the household appliance door comprises an electromagnetic actuator which is designated as a whole by 152. The actuator 152 has a magnet 154 with an armature, which is not represented. The control of and energy supply to the actuator 152 takes place by way of a fifth connection contact 156 and a sixth connection contact 158, which are formed as rigid, stiff conductors and serve the purpose of connection to the above-mentioned plug connection. The actuator 152 also has an actuating plunger 160 which is actively connected to the armature of the magnet 154 and can be actuated by this.
The locking and unlocking device also comprises a rotary slide 162 which serves to lock and unlock the main slide 104. The rotary slide 162 is rotatably mounted in the housing shell 102. A return spring 164, the function of which is described in detail in the following, can act on the rotary slide 162 in accordance with the position thereof. The rotary slide 162 has a prolongation 165 which, as illustrated in detail in the following, can interact with the first locking contact conductor 138 and with the return spring 164. A detent clip 166 can interact with the rotary slide 162 such that the rotary slide 162 is retained in a position which is suitable for locking, as described in detail in the following.
An electrical equivalent circuit diagram of the door lock 100 is shown in FIG. 4.
The operation of the door lock 100 is described in the following.
FIG. 1 shows the door lock 100 in a state in which the household appliance door is at least partly open, i.e. is neither in the closed nor in the locked state. In this state the main slide spring 106 acts on the main slide 104 such that this is pushed to the left. In this respect the main slide spring 106 is dimensioned such that, on account of an active connection of its end 116 with the structure 108, the first door contact conductor 118 is retained against its bias in the position which is shown in FIG. 1. The first and second door contacts 112 and 114 are as a result separated from one another. The door contact switch 110 is therefore open and indicates that the household appliance door is not closed.
The rotary slide 162 is retained in the position which is shown in FIG. 1 by a torsion spring, for example, which is not shown. In an embodiment which is not represented the return spring 164 is configured such that, for the state according to FIG. 1, it acts on the prolongation 165 and thereby retains the rotary slide 162 in the position which is shown in FIG. 1; it is then possible to dispense with the above-mentioned torsion spring, which is not shown. Here the rotary slide 162 acts by means of a prolongation or stop 170 against the biasing force of the first locking contact conductor 138 such that the first locking contact conductor 138 is retained in the position which is shown in FIG. 1. The first and second locking contacts 132 and 134 are separated from one another, the locking contact switch 138 is therefore open and indicates that the household appliance door is not locked.
FIG. 2 shows the door lock 100 in a state in which the household appliance door is closed, but not (yet) locked. The closure of the household appliance door causes the main slide 104 to be moved to the right against the force of the main slide spring 106. On account of its bias, the first door contact conductor 112 can in this case move such that the first and second door contacts 112 and 114 are brought into contact with one another. According to FIG. 2, this is achieved by the movement of the main slide 104 to the right terminating the active connection between the free end 116 of the first contact conductor 118 and the structure 108. The door contact switch 110 is now closed and indicates that the household appliance door is closed. The states of the rotary slide 162 and of the locking contact switch 130 have not changed in any way here with respect to FIG. 1.
FIG. 3 shows the door lock 100 in a state in which the household appliance door is closed and locked. This state is achieved by activating the actuator 152 in order to achieve a movement of the actuating plunger 160 to the left. The actuating plunger 160 then acts on the prolongation 165 and rotates the rotary slide 162 clockwise until a structure (e.g. a link connection), which is not represented, of the rotary slide 162 interacts with the detent clip 166 such that the rotary slide 162 is retained in the position which is shown in FIG. 3. The active connection between the prolongation 170 and the first locking contact conductor 138 is then terminated. On account of its bias, the first locking contact conductor 138 takes up the position which is represented in FIG. 3. The first and second locking contacts 132 and 134 are brought into contact with one another. The locking contact switch 130 is therefore closed and indicates that the household appliance door is locked.
In order to enable the household appliance door to be opened, the household appliance door has to be unlocked. The actuator 152 is activated again for this purpose. The resultant movement of the actuating plunger 160 to the left rotates the rotary slide 162 clockwise slightly against the action of force of the return spring 164, with the active connection of the structure, which is not shown, of the rotary slide 162 with the detent clip 166 being terminated and a rotation of the rotary slide 162 anti-clockwise being possible. The rotation of the rotary slide 162 back into its position which is represented in FIG. 2 or FIG. 1 takes place through the torsion spring, which was mentioned with reference to FIG. 1 and is not represented, and initially on account of the active connection between the return spring 164 and the prolongation 165. This rotation can also be effected by the return spring 164 alone, if this is configured such that it can also act on the prolongation 165 for the state according to FIG. 1.
The door lock 100, which is a representative example of known door locks of the type initially mentioned, has disadvantages like the latter. In order to connect the door lock 100, a plug connection with a total of 6 plug contact connection receptacles is required in order to accommodate the six connection contacts 122, 128, 142, 150, 156 and 158. The resultant construction space for a plug connection is a disadvantage, as corresponding construction space must also be provided on the household appliance side. The number of plug contact receptacles on the plug connection side is also a disadvantage, because—on the account of the structural and material expenditure—it entails corresponding production costs. This also applies to the actual door lock 1, where the total of six connection contacts entails corresponding construction space and expenditure.
A further disadvantage lies in the operational reliability of known door locks of this kind. If the actuator 152 is activated such that the rotary slide 162 is brought into the locking position which is shown in FIG. 3, although the door contact switch 110 is not closed, the door lock 100 may sustain damage if the household appliance door is closed when the door lock 100 is in a state of this kind.
Moreover, faulty operation of the household appliance as a whole may occur. If the actuator 152 is actuated as mentioned above, this results in the closure of the locking contact switch 130. The closed state of the locking contact switch 130 usually indicates to the household appliance control that startup is permissible. If, however, the household appliance door is not closed in a situation of this kind, injuries may occur through a drum rotating in the household appliance, water may escape in the case of household appliances carrying water and heat may escape in the case of driers and cookers.